CVE-2026-23901
Severity CVSS v4.0:
LOW
Type:
Unavailable / Other
Publication date:
10/02/2026
Last modified:
10/02/2026
Description
Observable Timing Discrepancy vulnerability in Apache Shiro.<br />
<br />
This issue affects Apache Shiro: from 1.*, 2.* before 2.0.7.<br />
<br />
Users are recommended to upgrade to version 2.0.7 or later, which fixes the issue.<br />
<br />
Prior to Shiro 2.0.7, code paths for non-existent vs. existing users are different enough,<br />
that a brute-force attack may be able to tell, by timing the requests only, determine if<br />
the request failed because of a non-existent user vs. wrong password.<br />
<br />
The most likely attack vector is a local attack only.<br />
Shiro security model https://shiro.apache.org/security-model.html#username_enumeration discusses this as well.<br />
<br />
Typically, brute force attack can be mitigated at the infrastructure level.